1. Field of the Invention
This invention pertains generally to the field of cockpit indicators or display units that provide flight information of a runway environment to the pilot or flight crew of an aircraft, and more particularly to synthetic vision systems (SVS), enhanced vision systems (EVS), or combined SVS-EVS systems.
2. Description of the Related Art
Modern avionics systems employ Head-Down Display (“HDD”) and Head-Up Display (“HUD”) systems for providing tactical flight information to the pilot. In an HDD system, a tactical flight display is mounted in the cockpit instrument panel directly in front of the pilot and below windshield level. To view the presentation of information on a display unit of an HDD system, a pilot must look down into the cockpit, causing him or her to take his or her eyes from the outside scene in front of the aircraft. In a HUD system, a HUD unit is mounted in front of the pilot at windshield level and is directly in the pilot's field of vision. The HUD system is advantageous because the display is transparent allowing the pilot to keep his or her eyes “outside the cockpit” while the display unit provides tactical flight information to the pilot.
Modern avionics systems may employ Synthetic Vision Systems (“SVS”), Enhanced Vision Systems (“EVS”), or combined SVS-EVS for displaying terrain information to both HDD and HUD systems. The SVS and EVS systems are advantageous because they may depict not only terrain but also obstacles and hard surfaces such as runways. The depiction of terrain and runway surfaces can increase a pilot's Situational Awareness and potentially provide a means of navigation. While the presentation of terrain and runway surfaces provides some advantages, an absence of runway visual cues in an SVS image, EVS image, or a combined SVS-EVS image limits the pilot's Situational Awareness of the runway environment. Such limitation could provide unnecessary challenges to a pilot who is operating an aircraft within the runway environment.